Waveburner no audio??

In Waveburner (v1.61), I can see my audio interface (RME Babyface). During playback, I can see the Peak/RMS meter in the Monitoring window, but I hear absolutely no sound.

Somehow the sound is getting lost between Waveburner's monitor of the master channel and the actual audio interface. All my other audio software plays back audio as expected.

I used Waveburner Prefs to set the audio to RME. Not sure what other troubleshooting is available.

I realize this is older software, and it's not officially supported, but would like to still use it if possible.

Thoughts?